Toxic adenoma: to biopsy or not to biopsy?

Toxic adenoma nodules rarely harbour cancer. Fine-needle aspiration (FNA) is often not done because of the rarity of these lesions being cancer, the difficulty in interpreting cytology in hyperthyroid patients and the rare precipitation of thyrotoxicosis. We present two young, Caucasian female patients aged 29 and 13 years who were each diagnosed with a toxic nodule categorised as benign and indeterminate respectively. They underwent hemithyroidectomy after being rendered euthyroid, however their histology unexpectedly revealed differentiated follicular cancer. Despite thyroid cancer being rare in patients with toxic adenomas, it should be considered when planning treatment, especially if there are risk factors for cancer, or suspicious features on ultrasound examination. A review of the literature shows that compared with adenomas in euthyroid patients, patients in this group are generally younger and predominately female. If an FNA is considered, it should be performed after the patient is rendered euthyroid.